1. Field of the Invention
The invention relates to a method of manufacturing composite materials based on a matrix comprised of thermoplastic resin, with reinforcement comprising a material based on discontinuous cellulosic fibers; and the product of such manufacture.
2. Background of the Prior Art
Cellulosic fibers are candidates for use as reinforcement at a level comparable to that of glass fibers, based on their mechanical characteristics and density. They have the advantage of cost, which supplies the motivation for developing techniques of employlng them.
There is known, e.g., from Eur. OS 0 O 62 533, a composite material comprising cellulosic fibers dispersed in a polyvinyl chloride matrix. According to this OS the cellulosic fibers are mixed with the matrix and a binding agent which improves adhesion between the fibers and the matrix.
There is also known, from U.S. Pat. No. 3,943,079, a means of promoting dispersion of discontinuous cellulosic fibers in a matrix comprised of an organic polymer, by pretreating the fibers with a composition comprising a lubricant and a thermoplastic polymer.
It is an object of the present invention to provide a method to manufacture composite materials comprised of cellulosic fibers in a matrix comprised of a thermoplastic resin, particularly an unsaturated polyester resin. The composite materials envisioned are highly disperse, in the form of compounds, felts, sandwich materials, etc.